Wireless telephony systems have traditionally been deployed using the concept of a cell, with one base station (BS) (also known as base transceiver station (BTS), Node B (NB), evolved NB (eNB), Access Point, communications controller, and the like) covering a given geographic area. BSs having the same or similar transmit power are typically used. In addition, in order to maximize coverage and to maintain interference at a reasonable level, careful site planning is used. A network deployed in such a manner is usually referred to as a homogenous network (HomoNet).
While such a deployment is optimal when the user density is uniform, in practice, it has serious shortcomings because the user density and traffic demand are rarely uniform. For example, in rural areas, roads are typically the only area where users are present. In urban or suburban areas, there are locations (hot spots) where the traffic demand is higher: such locations may comprise shopping malls, hotels, conference centers, and the like.
In order to improve coverage and user satisfaction, it may be advantageous to cover these hot spots of traffic demands with Low Power Nodes (LPNs). For instance, lower power base stations can be deployed to, e.g., cover lobbies of hotels, portions of shopping malls, and the like. The coverage of such a base station is referred to as a pico cell. When the base station transmit power is even lower, e.g., to cover a single residential unit, the coverage of such a base station is referred to as a femto cell. A network comprising regular base stations and pico cells and/or femto cells is referred to as a heterogeneous network (HetNet).
HetNets present new challenges to the deployment of a cellular system. In particular, the cellular layout may not be as regular as for a HomoNet since it is dependent on the hot spot locations. In particular, it may well happen that a LPN is located close to another base station. The close proximity can create a high level of interference for both user equipment (UE) (also known as mobile station (MS), terminal, user, subscriber, wireless node, and the like) and BSs.
In the Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) Release-10 technical standards, transmissions from the BS comprise both data channels and control channels. The interference can affect both the data channels and control channels. While solutions exist to mitigate interference on the data channels, no such solution has been defined yet for the control channels.